1. Field of the Invention
The present invention relates to a method of synchronization applied to databases in a network management system for establishing synchronization between a database of a managing system and a database of a managed system.
Network management can be classified into for example management of the configuration for managing the constituent elements of a network, management of faults for the detection, analysis, notification, and restoration etc, of faults, management of performance for managing response performance etc., management of security for preventing unauthorized access etc., and management of costs for managing the amount of use of lines etc. A variety of management methods have been already proposed in correspondence with the different sizes of networks etc. For example, a method of managing a network individually for each network element such as exchanges and multiplexers and a method of centrally managing a plurality of network elements are known, and generally such managements are achieved by setting up the databases independently.
In a network management system by treating network elements etc. as managed systems and by providing a managing system for centrally managing these managed systems, synchronizing processing becomes necessary for matching the content of the database set up in the managed system with the content in correspondence with the managed system set in the database of the managing system.
2. Description of the Related Art
Various methods have been already proposed as the method of synchronization for making the contents of a plurality of distributed databases consistent with each other. For example, there is a method in which, when a request is made for updating a database, that database is locked to reject requests for update and after the update of the database, the lock is released. In this method, however, the above mentioned lock is carried out every time the request for updating the database is generated, therefore there was a problem that the processing became complicate. Further, a method has been known in which a time stamp is given to every record in the database, the time stamp is referred to at the time of update of the database, and the update is performed using the record given the newest time stamp.
Further, there also exists a system in which a central computer and a remote computer each having its own database are connected by communication lines and records given time stamps are stored in each database. At the time of update of the database, a record having a newer time stamp in comparison with the time stamp contained in the request for update information for the database is read, this record is compressed to an update information file and transmitted, and this update information file is stored once in a buffer and then opened up in the database to perform the update processing (for example, refer to Japanese Unexamined Patent Publication No. 5-204739).
In the prior art method of synchronization of databases, a request for updating one database is generated in response to an update of another database in which the update of the former database is carried out in, for example, record units. In order to reduce the frequency of transfers of data in this case, in the related art, the transfer data was compressed to store into the file.
A system having a plurality of network elements such as exchanges and multiplexers is provided with a database for every network element and a managing system for managing these network elements as managed systems. The managing system has its own database storing the same content as the databases for each network element to operate and maintain the system.
Frequently, the network elements as managed systems are made by different manufacturers and are therefore different in configuration. Therefore, the content of the database for each network element as a managed system becomes different. Accordingly, the reconfiguration of the databases in the network elements become, due to the establishment of the database in the managing system and the reconfiguration of the database in the managing system, complex. This becomes a problem in the operation of the system.